Four Years After 2011 Earthquake, Tsunami: Japan Copes With Leftover Radioactivity at Fukushima

As the four-year anniversary approaches, Japan continues to recover from the devastating earthquake and tsunami that struck in March of 2011, while debris washes up thousands of miles away.

The magnitude-9.0 temblor struck on March 11, 2011, with an epicenter 129 km (80 miles) east of Sendai, Honshu, Japan, at 2:46 p.m. local time, according to the USGS. Massive tsunami waves hit the northeast coast of Japan 50 minutes later.

The catastrophe killed 15,703 people, injured 5,314 others and 4,647 remained missing, the USGS reported. At least 332,395 buildings were destroyed or damaged.

The earthquake and tsunami irreparably damaged the Fukushima Daiichi Nuclear Power Station. Nuclear reactor cores in Units 1, 2 and 3 melted because of the loss of coolant, which was cut by power outages. Explosions occurred after hydrogen built up to excessive amounts in the containment buildings.

Ongoing Problems in the Wake of the Japan Earthquake, Tsunami

Radioactivity released as a result of the Fukushima accident continues to be a problem at the site, which the Tokyo Electric Power Co. (TEPCO) is decommissioning.

A radioactive "puddle" was discovered in early March on the roof of one of the damaged buildings, TEPCO said. In late February, engineers also detected a rise in the radioactivity of drainage water, some of which went into the ocean.

The Associated Press reported that a remote-controlled robot will be used in April to investigate damage in the Unit 1 reactor.

Concerns have been raised about future Japanese natural disasters and emergency response in the wake of March 2011 tsunami.

There have been a few volcanic eruptions since 2011 and several earthquakes, mostly relatively small, over the past few years. One of the stronger quakes was the 7.3-magnitude earthquake near Kamaishi on Dec. 7, 2012.

Mount Ontake on the island of Honshu erupted on Sept. 27. 2014, killing 57 people. Typhoon Phanfone then raked the region a week after Ontake eruption.

Tsunami Debris Washes Up Thousands of Miles Away

Some evidence of the natural disaster has reached thousands of miles. Debris suspected to be from the March 2011 earthquake and tsunami that rocked Japan continues to make its way across the Pacific Ocean, landing on United States shores.

Hundreds of marine debris sightings have been reported along the British Columbia and U.S. Pacific coasts, the National Oceanic and Atmospheric Administration's Marine Debris Program said.

Small plastic bottles to abandoned boats have been found, but less than 50 of the sightings have been confirmed to be from the tsunami, NOAA said.

The North Pacific Subtropical Convergence Zone is one of the major currents moving from Japan toward the U.S., AccuWeather.com Senior Meteorologist Jason Nicholls said.

About 1.5 million tons of debris were estimated to be deposited in the Pacific Ocean immediately after the earthquake, the Japanese government said. Another 3.5 million tons are reported on the seabed along Japan's coast.

"Several ocean currents could have brought debris from Japan to the western coasts of Canada and the U.S.," Nicholls said.

A possible debris sighting occurred on March 2 when a woodworker found a log believed to be crafted in Japan on the North Coast at Santa Cruz, California, the Santa Cruz Sentinel reported.